Concrete walls cause rust stains on wallpaper; new construction;

Hello everyone,

we are currently building a semi-detached house. During an inspection, I have now discovered that rust stains are appearing on the wallpaper from the concrete pillars. I suspect this comes from the tie wire, the reinforcing steel is not visible. I want to be somewhat prepared when I make a complaint. Should the concrete wall have been treated before wallpapering, or is the cheap variant sufficient in an emergency, simply repainting the wallpaper in the hope that no further rust will occur under normal room humidity? Unfortunately, complaints are not always successful with our general contractor.

Thank you very much for your support!

Painting doesn't help. They will come back.

Remove the wallpaper, sand the spots, fill, [neue Tapete].

We had rust stains on corner beads that kept bleeding through. A painter then recommended an insulating spray. Treated with it and painted over. Nothing comes through anymore. Unfortunately, I no longer know the name of the spray.

Hi,

I already replied to the same problem in another thread.

It is probably due to the aggregate of the concrete.

Moin, habe auf gleiches Problem in einem anderen Thread bereits geantwortet. Dürfte aus der Gesteinskörnung des Betons kommen.

If at all, rust is probably only present if there is iron. (at most possible with steel fiber concrete)

I do not understand why one rejects such pompous answers when obviously one does not have sufficient knowledge about it.

As is known, the aggregate is a natural material. And as should be known, there are also aggregates with an iron content. If such an aggregate is present, these damages can occur.